1. Field of the Invention
This invention relates generally to loading cylindrical objects into containers, and more specifically, to vacuum transfer for packing in a box successive, separate layers of shotgun shells having a predetermined arrangement.
2. Description of the Prior Art
The present invention may be used whenever high speed, automated packing of objects in separate layers is necessary. It is particularly useful, however, where cylindrical objects such as loaded shotgun shells must be packaged carefully in a predetermined manner for reasons of safety.
Loaded ammunition contains live primers which are percussion sensitive and can be detonated by impact. The primer component is located in the cap or head of the shell, with the primer surface intended to receive impact exposed at the center of the cap. In order to prevent accidental discharge during handling and transportation, it is important that the shells are packed tightly to prevent dislocation and movement within the box. Peripheral liners along the sides of the box have been used to increase box wall integrity and also to ensure a tight fit. Chipboard strips have also been used to separate the rows of shells in a layer, thus maintaining the shells in each row and preventing random dislocations during handling and shipment.
Several prior art devices have been suggested for packing objects by vacuum pickup. For example, U.S. Pat. No. 3,929,234 to W. H. Warren describes a vacuum transfer device which carries eggs from storage cartons where the eggs have one array or spacing to an egg conveyer where they are to have a different spacing. Lifter plates with a plurality of vacuum cups are used for the egg transfer operation, the separation between the vacuum cups being adjustable so that the egg spacing may be modified during transfer.
Similar vacuum suction cups are used in a number of packing systems which pick up and package fruit. Typical of these is U.S. Pat. No. 3,928,942 to Paddock et al which discloses a pickup head equipped with multiple vacuum cups. Panels are used for guiding the pickup head into the box to pack the fruit.
Industrial shotgun shells are typically packed in cardboard boxes with hinged flaps. High speed, automated packing of such boxes requires that they be conveyed empty to the loading station with the top flaps in a position which will not interfere with the packing machinery. Typically, the top flaps are partially open when conveyed to the loading station, but usually must be folded outward just prior to loading in order not to interfere with the packing of the box. If the flaps are not at the proper angle when they arrive at the loading station, jams may occur, thus stopping the packing machinery.
Various prior art devices have been suggested to fold one or more of the flaps or to position the flaps properly for loading. For example, U.S. Pat. No. 3,662,516 granted to J. A. Wiseman describes a means for opening and closing box flaps before and after packing which includes suction cups mounted on levers arranged to pivot about the axis of the flap score line. Also, U.S. Pat. No. 3,452,653 granted to J. C. Berney describes a somewhat more complicated flap folding mechanism which includes flap folding arms mounted pivotally above and parallel to the flap crease line. The aforementioned Paddock et al patent also discloses a flap folding mechanism whereby, as the box is elevated, each of the flaps will encounter a corresponding fixed rod which is inclined upward to lift each flap against a corresponding fixed upper rod.